The legal answer can be found on the company’s website, in smaller print:

“Lifeline Skin Care and its affiliates do not guarantee specific results. Results may vary.”

It’s one of many cosmetic products to hit the market in recent years with claims of using human or plant-based stem cells to help restore the appearance of youth.

Many of these products — including this one — do moisturize and improve the appearance of skin, at least according to anecdotal evidence.

The question, experts say, is whether any improvement can be attributed to the stem cell science, a budding field of regenerative technology that’s largely unproven by U.S. scientific standards.

“Stem cells that are in contact with skin are not really alive anymore,” said Margaret Foster Riley, a law professor and expert on food and drug law at the University of Virginia. “So I don’t really see how a stem cell product is working on the skin. I suppose some of them may actually work in a way that cosmetics work otherwise, because of moisturizing capability. But it’s not stem cell capability that’s working there to the degree we know how stem cells work.”

Much is unknown about how — or if — these ingredients work because cosmetic products in the USA aren’t held to the same regulatory standards as new drugs. To gain approval for widespread use in this country, new drugs must show they are safe and effective based on data from long and expensive clinical trials.

By contrast, over-the-counter cosmetics generally aren’t subject to this same pre-market approval. Companies just have to be careful about what they claim the products do. If they promise to change the structure or function of the body, that would make them a drug requiring pre-market testing.

Other cosmetic companies claim to use plant-based stem cells. In a strike against such competition, Lifeline Skincare notes that it uses stem cells derived from unfertilized human eggs, not plant stem cells. The company says it uses “the same human stem cells that are active early in life to create new, young skin.”

“We haven’t seen clinical studies to support or prove that human skin responds or relates to plant stem cells,” the company’s website says.

Yet few have seen any rigorous studies to determine if human skin responds to human stem cell ingredients, either.